Tuning van der Waals Heterostructures with Near-Field Electrostatics

Recent advances in the fabrication and characterization of van der Waals heterostructures have demonstrated large tunability of their optoelectronic properties through the control of the microscopic parameters of the interface, such as the local atomic registry, strain and rotation. Beyond the quantum mechanical coupling between adjacent layers, 2D materials can impact and be impacted by the local electrostatic potential. At typical 2D-2D and 0D-2D materials distance (~3-5Å), near-field effects–resulting from the high multipoles of the electronic density–can be dominant.<br/>In this work, we develop a theory of the near-field electrostatic effects of self-assembled organic layers and 2D materials. We show using density functional theory that the electrostatic potential of a vast number of experimentally achievable organic layers and 2D materials is well approximated by a discretized charge density model. This model can be derived from the atomic positions and multipoles of the electronic density. We derive simple analytical expressions of the electrostatic potential V(x,y,z) in the case of organic layers and h-BN, mono- and dichalcogenides, and show their applicability in tuning the electronic structure of 2D materials and van der Waals heterostructures.